Apparatus for manufacturing pretensioned reinforced concrete slabs



Dec. 21, 1965 R. J. HUMMEL ETAL 3,224,064

APPARATUS FOR MANUFACTURING PRE-TENSIONED REINFORCED CONCRETE SLABS Filed Aug. 2, 1962 2 Sheets-Sheet 1 I NVENTORS fizz/47d A DEW/Z 1;:

ATTORNEYS De 2 1965 R. J. HUMMEL ET-AL 3,224,064

APPARATUS FOR MANUFACTURING PRE-TENSIONED REINFORCED CONCRETE SLABS Filed Aug. 2, 1962 2 Sheets-Sheet 2 INVENTORJ Rolefi/ Lil/21m 7726/ BY flamas Q Rem Zara flan/div! L Denn 1;;

m by A TTORNEYS United States Patent 3,224,064 APPARATUS FOR MANUFACTURING PRE- TENSIQNEI) REINFORCED CONCRETE SLABS Robert J. Hummel, Pompano Beach, and Thomas D. Rembert and Howard L. Dennis, Fort Lauderdale, Fla, assignors to Houdaille Industries, Inc., Buffalo, N.Y., a corporation of Michigan Filed Aug. 2, 1962, Ser. No. 214,272 Claims. (Cl. 25-41) This invention relates to improvements in an apparatus for manufacturing pre-tensioned reinforced concrete slabs.

A principal object of the invention is to provide an improved apparatus for manufacturing pre-tensioned reinforced concrete slabs in such a manner as to prevent slippage of the reinforcing strands or wires with respect to the concrete slab.

A further object of the invention is to provide an improved form of apparatus for manufacturing pre-tensioned concrete slabs constructed with a view towards giving a better mechanical bond between the reinforcing strands than is attained by former apparatus, in order to prevent slippage of the reinforcing strands with respect to the cement.

Still another object of the invention is to prevent false setting of the cement of a concrete slab manufacturing apparatus by utilizing vibrators to compact the cement instead of the usual tampers, heretofore used for this purpose.

A still further object of the invention is to provide an improved form of apparatus for manufacturing pretensioned reinforced concrete slabs, in which the concrete is compacted along the reinforcing strands by spaced vibrator shoes extending between the strands and compacting and forcing the cement over the strands, and by completing the compacting operation by high frequency vibrators spaced to the rear of the vibrator shoes.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein:

FIGURE 1 is a diagrammatic side elevational view of an apparatus for manufacturing pre-tensioned concrete slabs constructed in accordance with the principles of the present invention;

FIGURE 2 is a partial fragmentary transverse sectional view taken substantially along line IIII of FIG- URE 1;

FIGURE 3 is a detailed view in side elevation of the compacting vibrator at the front of the machine.

FIGURE 4 is a fragmentary bottom plan view of the vibrator shown in FIGURE 3;

FIGURE 5 is a fragmentary top plan view of the vibrator hown in FIGURES 2 and 3;

FIGURE 6 is a fragmentary detail view in side elevation of the high frequency vibrator spaced toward the rear of the machine;

FIGURE 7 is a fragmentary plan view of the vibrator shown in FIGURE 6; and

FIGURE 8 is a detail View of the high frequency vibrator looking toward the rear end of the vibrator.

In the embodiment of the invention illustrated in FIG- URE 1 of the drawings, I have diagrammatically shown an apparatus for manufacturing pre-tensioned, reinforced concrete slabs which may be used for roofs, walls, or floors of buildings. The apparatus includes generally a frame 11 having three vertically extending bins 12, 13, and 14 supported thereon and containing mixtures of cement and aggregate of different consistencies. The

frame 11 has longitudinally extending beams 15 extending across the top thereof and adapted to suspend the machine from a gantry (not shown) which may be a four legged gantry and carries the apparatus along the floor in the direction of the arrow in FIGURE 1.

The front bin 12 is adapted to contain a mixture of cement and relatively coarse aggregate and deposit the mixture on a flat pallet resting on the floor to form the bottom layer of the concrete slab. The intermediate bin 13 is adapted to contain a mixture of cement and aggregate, which may be finer than the aggregate in the front bin 12, to deposit an intermediate layer of concrete on top of the base layer deposited by the bin 12. The rear bin 14 is adapted to deposit a top or finishing layer of cement and fine aggregate to form the finishing layer of the slab.

Parallel spaced channels 15* having outwardly facing flanges 15 are suspended from the main frame 11 on depending legs 15 and 15 The plane inner faces of said channels serve as side forms for the slab.

Referring now to the front bin 12 and the means for controlling the discharge of concrete therefrom, the bin 12 has a rearwardly opening discharge duct 16 at its bottom closed by a vertically adjustable gate 17, which may be moved vertically by uitable adjusting mechanism such as, adjusting screws and nuts 18. The adjustable gate 17 has a plurality of downwardly opening slots 19, passing along pre-tensioned reinforcing wire-s 21.

Spaced rearwardly of the gate 17 is a vibrator 23. The vibrator 23 may be an electric vibrator of a type in which eccentric weights are rotated at high rates of speed, such as a Weiler high frequency vibrator. This vibrator is a commercial article of manufacture and of itself is no part of the present invention, so need not herein be shown or described further, except to point out that it may be operated at a frequency of from 9000 to 10,000 v.p.m. The vibrator 23 has a pedestal 24 at opposite ends thereof, which may be bolted to lugs 25 mounted on a base plate 26, and extending upwardly therefrom. The base plate 26 extends transversely of the frame 11 between laterally spaced longitudinally extending beams 27, extending between the bins 12 and 13.

The vibrator 23 and base plate 26 are suspended from the beams 27 on links 29. As shown in FIGURE 2 and 3, four links 29 are provided at each end of the plate 26. The links 29 extend through blocks 30 and the horizontal legs 31 of longitudinally spaced guide angles 32. The blocks 30 may be welded or otherwise secured to opposite sides of the horizontal legs 31 of said guide angles. A resilient ball like bearing member 33, which may be made from rubber, neoprene or a like material is supported on the top block 30 and forms the support for the link 29. Lock nuts 35 threaded on the upper end of the link 29 support said link on the resilient ball 33. The lower end of the link 29 extends through a horizontal leg 36 of an angle bracket 37, mounted on and extending upwardly from a base plate 26. A resilient ball like hearing member 38 is mounted on the under side of the leg 36 and may be like the ball-like bearing member 33. A not 39 threaded on the lower end of the link 29 retains said rod to said ball-like bearing member. The horizontal leg 36 of the angle bracket 37 slidably engages the inside of a vertical leg 40 0f the bracket 32. The suspension connections of all four links 29 for the plate 26 will thus accommodate the vibrator 23 to impart vibratory movement to the plate 26, and the resilient bearing members 33 and 38 reduce the amount of vibration in the machine itself.

Suspended from the plate 26 are a series of plow-like elongated compacting shoes 41, 41 and 43, 43. The compacting shoes 41, 41 and 43, 43 extend in the spaces between the reinforcing strands 21, and by their vibratory action compact the layer of concrete beneath said strands and about said strands. The compacting shoes 41 and 43 are suspended from the bottom of the plate 26 on the vertical legs of individual angle brackets 44, the horizontal legs of which abut the bottom of the plate 26 and are bolted or otherwise secured thereto.

The compacting shoes 41 are shown in FIGURES 2, 4, and 5 as being suspended from angle brackets 44 at the forward and rear end portion thereof and as being of a generally boat shape in plan tapering at their forward end portions into plow-like points 45, extending for the height thereof. The bottoms of the compacting shoes 41 and 43 are shown in FIGURE 2 as being rounded, as indicated by reference character 46.

Thus as concrete mixture is discharged from the bin 12 under the control of the gate 17 and the machine is advancing along the floor in the direction of the arrow shown in FIGURE 1 with the pointed ends 45 of the compacting shoes 41 and 43 leading, assuming the pre-tension wires are in place and the vibrator 23 is in operation, the vibrating compacting shoes 41 and 43 by their vibratory motion will compact the concrete beneath and along each side of the reinforcing strands or wires and at the same time will plow the concrete to each side of said compacting shoes and generally compact the concrete over the reinforcing strands and form concave grooves along the first layer of the slab, compacted to receive reciprocating cores (not shown) following said compacting shoes and forming voids in the slab extending for the length thereof. The cores are conventional and are mounted rearwardly of the vibrator 23 and are no part of the present invention so are not herein shown or described further.

The cores (not shown) follow the compacting shoes 41 and 43 and are covered with concrete during the travel of the machine by concrete discharged the-reover, forming an intermediate layer of the slab and smoothed and compacted by a series of individual high frequency vibrators 47, 47 diagrammatically shown in FIGURE 1, and shown in FIGURES 6, 7 and 8 as being pivotally supported on a transverse shaft 49 for free movement with respect thereto.

The vibrators 47 are shown as being high frequency fluid operated vibrators including vibrating motors 50, which may be operated by air or liquid and are commercial forms of vibrators, so need not be herein shown or described further. Each vibrator motor 50 is mounted on and extends upwardly from the top surface of a vibrating shoe 51. Each vibrating shoe 51 has a flat bottom surface rounded or beveled at its advance end, as indicated by reference character 5.3 and has parallel spaced cars 55 extending upwardly therefrom and forming a support for the motor 50 and a mounting for the transverse shaft 49. The transverse shaft 49 and vibrators 47 are suspended from longitudinally extending frame members 56 of the machine frame, on links 57 pivotally connected to the shaft 49 at their lower ends and extending through balllike resilient mounting members 59 at their upper ends, and suitably connected thereto. The ball-like mounting members are shown in FIGURE 6 as leading the vibrating shoes 51. Compression springs 60 may be connected between the frame 11 and the shaft 44, to bias the shaft 49 in a downward direction and assure that the vibrating shoes 51 have firm compacting engagement with the newly laid concrete.

Each vibrator motor 50 is operated at a frequency of from 4000 to 16,000 vibrations per minute. The vibrators 47, therefore, serve to give additional compaction to the concrete that covers the cores and also to compact the concrete disturbed by the arms (not shown) controlling oscillation and travel of the cores with the machine.

Rearwardly of the high frequency vibrators 47 is a tamper 65. The tamper 65 serves to give a slight amount of finishing compaction to the concrete but serves primarily to level the concrete to accommodate a screed 66 to provide a finishing surface to the slab. The tamper 65 may be of a well known form, moved vertically by eccentrics 6'7 driven from a motor 69. The eccentrics 67 are connected with the tamper 65 through eccentric straps 70 and links 71. The screed 66 may also be of a well known form of adjustable screed suspended from the rear end portion of the machine frame by links 73.

In operation of the machine, as the machine moves in the direction of the arrow in FIGURE 1,. assuming the reinforcing strands are in place and tensioned, the concrete is discharged through the discharge duct 16 of the bin 12 under control of the gate 17, to pour the bottom layer of the slab over the pre-tensioned strands 21. The vibrating compacting shoes 41 and 43 are set into operation during this discharge operation and during travel of the machine in the direction of the arrow, to compact the concrete mixture as it is laid, and also to compact and plow the concrete around the reinforcing strands 21 and to form grooves for the oscillating cores (not shown), following the compacting shoes 41 and 43 in the channels formed thereby.

As the machine advances to compact the advance end of the slab and provide formed channels for the cores therein, concrete is discharged from the bin 13 over the oscillating cores (not shown), and this newly laid concrete is compacted by the high frequency vibrators 47, compacting the concrete covering the cores, and maintaining the concrete, which has been disturbed by the arms (not shown) that control the oscillation of the cores (not shown) in position and assuring compaction and leveling of the disturbed areas.

The tamper 65 then serves to give a slight amount of additional compaction to the concrete previously discharged and discharged from the bin 14, but principally levels the concrete to assure a level slab, which is further smoothed and leveled by the screed 66 following the tamper 65.

It may be seen from the foregoing that in place of the usual tamping of the slabs laid by concrete slab making machines, we instead compact the layers of concrete by vibratory compacting shoes compacting the concrete around the pre-tensioned reinforming slabs, and forming channels along which the cores are laid, and that the concrete covering the cores is further compacted by the high frequency vibrating shoes 47, the tampers serving only to finish compaction of the slab and level the slab, where there may have been an uneveness of feed.

It may further be seen that by the utilization of the vibrators for the two layers of concrete, the first of which forms channels for the cores and compacts the concrete around the pre-tensioned strands, the concrete is more efficiently compacted around the reinforcing strands and along and over the cores and leveled, and that this vibrating compaction action obviates false setting of the cement and gives a firm mechanical bond around the reinforcing strands eliminating the strand slippage that has heretofore been prevalent in the manufacture of reinforced concrete slabs.

It should further be noted' that the vibrators give a greater degree of compaction of the con-crete and also provide a more dense product in addition to eliminating strand slippage.

While we have herein shown and described one form of which our invention may be embodied, it may readily be understood that various variations and modifications in the invention may be attained without departing from the spirit and scope of the novel concepts thereof as defined by the claims appended hereto.

We claim as our invention:

=1. In an apparatus for manufacturing concrete slabs having spaced pre-tensioned strands extending therealong, a mobile frame suspended for movement along the ground in vertically spaced relation with respect thereto,

a first bin mounted on said frame adjacent the forward end thereof, a second bin mounted on said frame and spaced rearwardly of said first bin, a vibrating compactor extending across said frame in the space between said first and second bins and suspended from said frame, said compactor having a series of parallel spaced elongated vibrating compacting shoes having advance plow-like ends for plowing the concrete over said strands, means for vibrating said shoes for compacting the concrete between and about said strands and forming channels between said strands, a transverse shaft extending across said frame rearwardly of said second bin and suspended from said frame and having a series of high frequency vibrating shoes individually pivoted thereto, said shoes having relatively flat compacting bottom surfaces for compacting the concrete laid by said second bin, links movably mounted on said frame at their upper ends and suspending said shaft from said frame for limited movement with respect thereto, spring means biasing said shaft and shoes in concrete compacting positions, and individual high frequency vibrators mounted on said shoes for independent floating engagement with the ground.

2. In an apparatus of manufacturing concrete slabs having spaced pre-tensioned reinforcing strands extending therealong, a mobile frame supported for movement in vertically spaced relation with respect to the ground, a bin mounted on said frame at the front end thereof and extending thereacross, a gate for said bin adjustably movable to regulate the discharge of concrete from the rear end of said bin and having a series of bottom opening slots therein for receiving the previously laid pre-tensioned reinforcing strands, a vibrating compactor suspended from said frame and including a plate having a vibrator on the top surface thereof, and having a series of parallel spaced plow-like vibrating compacting shoes suspended from said plate having generally rounded bottoms and advance ends tapering to a point, and positioned in the spaces between the bottom opening slots in said gate, to extend between the reinforcing strands and compact the concrete thereabout and form channels therein, a second bin spaced rearwardly of said first bin and said compacting shoes, and other high frequency vibrating shoes suspended from said frame and spaced rearwardly of said second bin and including a series of relatively flat bottomed shoes mounted for independent vibrating movement with respect to each other in side by side relation with respect to each other, individual fluid pressure operated vibrators mounted on said shoes and a shaft extending transversely of said frame and suspended therefrom in advance of said shoes and having said shoes freely pivotally mounted thereon for independent floating engagement with the ground.

3. In an apparatus for manufacturing concrete slabs having spaced pre-tensioned reinforcing strands extending therealong, a mobile frame mounted for movement along the ground in vertically spaced relation with respect thereto, parallel spaced side forms suspended from opposite sides of said frame, three bins mounted on said frame and spaced therealong for discharging concrete through the bottoms thereof in the space between said side forms, to pour a slab in layers during travel of said frame, a first advance bin having an advance adjustable gate mounted at the lower rear end thereof for regulating the discharge of concrete from said first bin, said gate having a series of bottom opening slots therein for receiving the previously laid pre-tensioned reinforcing strands, a vibrating compactor suspended from said frame behind said gate and including a series of laterally spaced compactor shoes positioned on opposite sides of said slots and extending in the direction of the strands and formed to plow and compact the concrete over and around the strands and to form channels in the slab, vibrating means for vibrating said compactor shoes, a series of flat bottomed high frequency vibrating shoes suspended from said frame and spaced rearwardly of said second bin and including a series of shoes having fiat bottoms, mounted in side by side relation with respect to each other for independent vibratory movement and having independent floating engagement with the newly laid concrete for compacting the layer of concrete laid by the second bin over the layer of concrete laid by the first bin, and a tamper spaced rearwardly of said third bin and mounted on said frame to extending thereacross for leveling and finish tampering the slab.

4. In an apparatus for manufacturing concrete slabs having spaced pre-tensioned strands extending therealong, a mobile frame, at least one bin for concrete mounted on said frame, concrete compacting means disposed rearwardly of said bin and drawn along the freshly laid con crete by said frame upon movement of said frame along the ground comprising, a series of freely movable concrete compacting shoes supported to extend across said frame in side-by-side relation with respect to each other, a transverse shaft extend-ing across said frame and having said shoes freely mounted thereon for individual pivotal movement about the axis of said shaft, an individual vibrator on each shoe, and means connecting said shaft to said frame comprising a pair of links forming coaxial pivotal mountings for opposite ends of said shaft, said links being suspended from said frame in advance of said shaft and being movably mounted thereon for angular movement relative to said frame in parallel vertical planes, and drawing said shaft and shoes along the freshly laid concrete in free floating compacting engagement therewith.

5. A concrete slab manufacturing apparatus in accordance with claim 4, wherein springs connected between said frame and shaft yieldably bias said shoes into engagement with the freshly laid concrete.

References Cited by the Examiner UNITED STATES PATENTS 1,920,716 8/1933 Schafer 2541 2,461,500 2/ 1949 Miller et a1. 25-41 2,962,785 12/ 1960 Young 25-41 XR 3,123,872 3/ 1964 Perlmutter 25-118 FOREIGN PATENTS 500,557 7/1951 Belgium. 1,008,180 5/ 1957 Germany. 1,036,742 8/1958 Germany. 1,03 6,743 8/ 1958 Germany. 1,084,186 6/1960 Germany. 1,118,684 11/ 1961 Germany.

J. SPENCER OVERHOLSER, Primary Examiner.

WILLIAM J. STEPHENSON, ROBERT F. WHITE,

MICHAEL V. BRINDISI, Examiners. 

1. IN AN APPARATUS FOR MANUFACTURING CONCRETE SLABS HAVING SPACED PRE-TENSIONED STRANDS EXTENDING THEREALONG, A MOBILE FRAME SUSPENDED FOR MOVEMENT ALONG THE GROUND IN VERTICALLY SPACED RELATION WITH RESPECT THERETO, A FIRST BIN MOUNTED ON SAID FRAME ADJACENT THE FORWARD END THEREOF, A SECOND BIN MOUNTED ON SAID FRAME AND SPACED REARWARDLY OF SAID FIRST BIN, A VIBRATING COMPACITOR EXTENDING ACROSS SAID FRAME IN THE SPACE BETWEEN SAID FIRST AND SECOND BINS AND SUSPENDED FROM SAID FRAME, SAID COMPACTOR HAVING A SERIES OF PARALLEL SPACED ELONGATED VIBRATING COMPACTING SHOES HAVING ADVANCE PLOW-LIKE ENDS FOR PLOWING THE CONCRETE OVER SAID STRANDS, MEANS FOR VIBRATING SAID SHOES FOR COMPACTING THE CONCRETE BETWEEN AND ABOUT SAID STRANDS AND FORMING CHANNELS BETWEEN SAID STRANDS, A TRANSVERSE SHAFT EXTENDING ACROSS SAID FRAME REARWARDLY OF SAID SECOND BIN AND SUSPENDED FROM SAID FRAME AND HAVING A SERIES OF HIGH FREQUENCY VIBRATING SHOES INDIVIDUALLY PIVITED THERETO, SAID SHOES HAVING RELATIVELY FLAT COMPACTING BOTTOM SURFACES FOR COMPACTING THE CONCRETE LAID BY SAID SECOND BIN, LINKS MOVABLY MOUNTED ON SAID FRAME AT THEIR UPPER ENDS AND SUSPENDING SAID SHAFT FROM SAID FRAME FOR LIMITED MOVEMENT WITH RESPECT THERETO, SPRING MEANS BIASING SAID SHAFT AND SHOES IN CONCRETE COMPACTING POSITIONS, AND INDIVIDUAL HIGH FREQUENCY VIBRATORS MOUNTED ON SAID SHOES FOR INDEPENDENT FLOATING ENGAGEMENT WITH THE GROUND. 